<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
</head>
<body>
  <h2>我是弹出子窗口</h2>
  <button id="popBtn">向窗口传递信息</button>
</body>
<script>
  var popBtn = this.document.querySelector('#popBtn')
  popBtn.onclick = function(e){
    window.opener.postMessage('我是子窗口的消息')
  }
</script>
</html>